Benzophenone ureas and method for utilizing the same

ABSTRACT

This invention provides for novel benzophenone ureas, a method for preparing the same, and a method for controlling undesirable broadleaf weeds and grasses therewith, wherein said benzophenone is represented by the generic formula: ##SPC1## 
     Where A and B each represent hydrogen, methyl, halogen, trifluoromethyl, or methoxy; R 1  and R 2  are taken singly or in combination and represent hydrogen, lower alkyl, alkoxy, alkoxyalkyl, cycloalkyl, cyclohetero, loweralkylamino, lower alkenyl or lower alkynyl, with the proviso that A is either meta or para to the --HN--CO--NR 1  R 2  substituent.

The present invention relates to novel benzophenone ureas having theformula: ##SPC2##

Where A and B represent a member selected from the group consisting ofhydrogen, methyl, halogen, trifluoromethyl, and methoxy; R₁ and R₂ eachrepresent a member selected from the group consisting of hydrogen,loweralkyl C₁ -C₄ , alkoxy C₁ -C₄, alkoxyalkyl C₂ -C₆, cycloalkyl C₃-C₆, cyclohetero, loweralkylamino C₁ -C₄, loweralkenyl C₂ -C₄, andloweralkynyl C₂ -C₄ ; and providing that the substituent represented byA is meta or para to the --NH--CO--NR₁ R₂ substituent. The inventionfurther relates to a process for preparing the said ureas. Stillfurther, this invention relates to a method for controlling undesirablebroadleaf weeds and grasses, utilizing the compounds of the ureasabove-identified.

In accordance with the process of invention, benzoylphenyl ureas (I) maybe prepared by a procedure involving the use of an appropriateaminobenzophenone (II).

As one embodiment of the invention, hereinafter termed embodiment (A),phosgene is passed through a solution of an aminobenzophenone (II) in anaprotic solvent, such as benzene, toluene, or xylene, in the presence ofa molar equivalent of anhydrous alkali metal carbonate, such as sodiumor potassium carbonate. Reaction temperature is generally maintained atbetween about 40° and 100° C., although somewhat higher or lowertemperature may be used. After removal of excess phosgene, anappropriate amine (NHR₁ R₂) in an aprotic solvent (e.g., benzene) isadded at about 0° C. to 20° C. to resultant so-formed benzophenoneisocyanate. In such reaction the intermediate, i.e., the benzophenone,is preferably in the same aprotic solvent. Usually, the desired productprecipitates and is filtered off. Crystallization is often necessaryfrom benzene in order to remove insoluble impurities, such ascarbanilide.

Graphically, the process of the invention may be illustrated in thefollowing manner: ##SPC3##

Where A, B, R₁ and R₂ are the same as defined above.

In an alternative embodiment of the present invention, hereinaftertermed embodiment (B), a substituted carbamoyl chloride is reacted withan aminobenzophenone (II) above in the presence of a base, such astriethylamine, pyridine, sodium carbonate, potassium carbonate, sodiumbicarbonate, and a solvent, such as acetone, ether, ordimethylformamide. The reaction mixture is heated to between about 50°and 80° C., and preferably between 50° and 60° C., to effect reaction.

In general, the reaction may be illustrated as follows, wherein A, B, R₁and R₂, are defined above. ##SPC4##

Advantageously, the compounds of the invention can also be prepared by athird embodiment (C), which involves reaction of the aminobenzophenone(II) with the appropriate substituted isocyanate in an aprotic solvent.This process is particularly effective for the preparation ofmonoalkylureas, since it provides such compounds in high yield. Thereaction may be graphically illustrated as follows wherein A, B, and R₁are as defined above. ##SPC5##

Illustrative aminobenzophenone reactants are: 4-aminobenzophenone,4-amino-4'-chloro-2-methoxybenzophenone;4-amino-2,4'-dichlorobenzophenone;4-amino-2-chloro-4'-methoxybenzophenone;4-amino-2,4'-dibromobenzophenone; 4-amino-2,4-dimethylbenzophenone;4-amino-4'-trifluoromethylbenzophenone; 4-amino-4'-methylbenzophenone;4-amino-4'-methoxybenzophenone; 4-amino-2,3'-dichlorobenzophenone;5-amino-2-chlorobenzophenone; 5-amino-2-bromobenzophenone;5-amino-2,4'-dichlorobenzophenone; 5-amino-2,4'-dibromobenzophenone;5-amino-2,3'-dimethylbenzophenone; and 4-amino-2-chlorobenzophenone.

In general, the aminobenzophenones are initially obtained by thereduction of nitrobenzophenone. For instance, one reduction methodinvolves the use of metal acid reduction as exemplified by iron andhydrochloric acid conducted in an ethanol-water medium. Othermetal-reducing agents are similarly suitable, as for instance, tin,stannous chloride, zinc, and other weak or strong mineral or organicacids, such as acetic acid or nitric acid. Solvents miscible with water,such as alcohols or even acetic acid may be used. Further, alkalinereducing conditions are also suitable; e.g., sodium dithionite in water,or zinc in aqueous alkali. Another method is the use of catalyticreduction employing hydrogen and catalysts, such as Raney nickel,ruthenium on carbon, palladium on carbon, or platinum oxide in analcoholic medium. The latter catalysts prevent dehydrohalogenation.

The nitrobenzophenones employed above can be prepared by aFriedel-Crafts benzoylation of a substituted benzene in the presence ofat least a molar excess of aluminum chloride, hydrogen fluoride or borontrifluoride.

The overall reaction including the reduction stage to obtain anaminobenzophenone where A and B are as defined above can be written asfollows: ##SPC6##

Advantageously, the compounds of the invention can be formulated inconventional type formulations; such as dusts, dust concentrates,wettable powders, liquid concentrates, or granular formulations.

The wettable powder formulations may be prepared by grinding togetherfrom about 25 to 75% by weight of the active benzophenone urea withabout 23 to 73% by weight of a finely divided solid diluent; such asattapulgite, bentonite, kaolin, talc, diatomaceous earth, or pumice, andadmixing therewith from about 1% to 5% by weight of an anionic-nonionicemulsifier and/or from about 1% to 5% by weight of a dispersing agent. Atypical anionic-nonionic blend which may be used contains the calciumsalt of myristylbenzene sulfonic acid and the oleate ester of apolyoxyethylene glycol (molecular weight = 350) in a 3 to 1 ratio. Alsouseful is the blend of calcium laurylpheno-sulfonic acid andpolyoxyethylene sorbitan monolaurate. Dispersing agents which may beused in these formulations include the mono-calcium salt of apolymerized alkylaryl sulfonic acid, the sodium salt of condensednaphthylene sulfonic acid, the alkali metal lignosulfonates.

Liquid concentrates may be prepared by dissolving from about 25 to 75%by weight of the benzophenone urea in from about 73 to 23% by weight ofan organic solvent, benzenes, toluene, xylene, and mixtures thereof,ketones (such as acetone, methylethylketone, or methylisobutylketone),or alcohols (such as methanol, ethanol, isopropanol, n-butanol orhexanol). Generally, from about 2% to 5% by weight of an emulsifier,such as named above, is also included in such formulations. Spreaders,stickers, surface active agents and the like, may also be added whendesired.

In practice, these wettable powder and liquid concentrate formulationsare usually dispersed in water and/or some other relatively inexpensivediluent and applied to the soil containing seeds or seedling plants ofundesirable broad leaf weeds and/or grasses or the foliage of suchplants to control the same.

For preemergence control of undesirable plants generally about 1 to 25pounds of the active compounds per acre, is effective, whereas,application of such compounds as postemergence herbicidal agents usuallyrequires only about 1/8 pound to 15 pounds, and preferably one eighthpound to 10 pounds per acre of the inventive compounds for effectiveweed and grass control.

Granular formulations, which are prepared by coating the surfaces of aninert carrier; such as ground corn cobs, sand, clay, or similarparticles, with from about 5 to 25% by weight, and preferably 10 to 15%by weight of the active benzophenone urea and particularly useful forpreemergence weed and grass control. These formulations lend themselvesto preplant incorporation techniques or to soil surface application.

The invention will be further illustrated in detail by the followingspecific examples. It should be understood, however, that although theseexamples may describe some of the more specific features of theinvention, they are given primarily for purposes of illustration, theinvention in its broader aspects is not to be construed as being limitedthereto. Unless otherwise specified, the parts and percentages are byweight.

EXAMPLE 1 Preparation of3-[3-Chloro-4-(p-chlorobenzoyl)phenyl]-1,1-dimethyl Urea, EmployingProcedure A Above

In a suitable reaction vessel was added anhydrous sodium carbonate (3.6grams, 0.034 mole) to 3-chloro-4-(p-chlorobenzoyl)aniline (9 grams,0.034 mole) suspended in toluene (350 ml.). Phosgene was then bubbledthrough the solution for an additional one and one-half hours. Aftercooling the reaction mixture, it was filtered and evaporated to recovera syrupy oil, 3-chloro-4-(p-chlorobenzoyl)phenylisocyanate. Dry benzene(200 ml.) was added to the syrup, and then with stirring, dimethylamine(10 grams) in benzene (100 ml.) was added. A white solid3-[3-chloro-4-chlorobenzoyl)phenyl]-1,1-dimethyl urea, was precipitatedand filtered off. There were recovered 10.2 grams of product amountingto a 88% yield and having a melting point equal to 170° - 172° C.Crystallization from benzene gave colorless plates possessing a meltingpoint equal to 173° - 174° C.

On Analysis in percent: Calculated for C₁₆ H₁₄ N₂ O₂ Cl₂ : C, 56.99; H,4.18; N, 8.31; Cl, 21.03.

Found: C, 57.01; H, 3.81; N, 8.19; Cl, 20.95.

EXAMPLE 2 Preparation of 3-(m-Benzoylphenyl)-1,1-dimethyl Urea EmployingProcedure B Above

Dimethylcarbamoyl chloride (7.5 grams, 0.07 mole) was added to asolution of 3-aminobenzophenone (10 grams, 0.05 mole) indimethylformamide (150 ml.), triethylamine (10 ml.) at 10° C. withstirring and ice cooling. The reaction temperature was next raised to60° C. for 20 hours, then cooled and poured onto ice water (500 grams)containing dilute hydrochloric acid. A tarry solid was obtained bydecanting off the aqueous organic solution. Purification was effected bydissolving the tarry solid in methylene chloride and passing through asilica gel dry column eluant methylene chloride. On elution withdichloromethane, the product, 3-(m-benzoylphenyl)-1,1-dimethyl urea, isobtained. Melting point was 104° -105° C. Crystallization frombenzene-hexane (9:1) mixture gave solid 109° - 110° C., which onbenzene-hexane crystallizations afforded a melting point of from 121° to122° C. identified as the desired urea by comparison with the sampleprepared from phosgene and dimethylamine.

Analysis Calculated for C₁₆ H₁₆ N₂ O₂ : C, 71.6; H, 6.0; N, 10.4. Found:C, 71.9; H, 6.24; N, 10.3.

EXAMPLES 3 - 21

In the examples which follow, aminobenzophenones are reacted inaccordance with Procedures A, B, or C outlined above to yield thestructures which are characterized and summarized in Table I below.

                                      TABLE I                                     __________________________________________________________________________                                                     Melt-                                                  Pro-                   ing Analysis (%)             Ex.                       ce-                                                                              Reaction         (%)                                                                              Point                                                                             Calcu-                   No.                                                                              Structure              dure                                                                             Solvent                                                                             Conditions Yield                                                                            ° C                                                                        lated                                                                              Found               __________________________________________________________________________        ##STR1##              A  toluene                                                                              ##STR2##  30 144.5- 145°                                                                C,71.6 H,6.0                                                                       C,71.6 H,6.1                                                                  N,10.6              4                                                                                 ##STR3##              C  dimethyl- forma- mide                                                                ##STR4##  28 215- 216°                                                                  C,70.9 H,5.6                                                                       C,70.7 H,5.3                                                                  N,11.0              5                                                                                 ##STR5##              B  dimethyl- forma- mide                                                               triethyl- amine at 60°                                                            5  121- 122°                                                                  C,71.6 H,6.0                                                                       C,71.9 H,6.1                                                                  N,10.4                                        A  toluene                                                                             50° C.                                                                            53 123.5-   C,71.5                                                 3 hours       125°                                                                            H,6.0                                                  COCl.sub.2             N,10.2              6                                                                                 ##STR6##              A  toluene                                                                             90° C. 1.5 hours COCl.sub.2                                                       84 166.5- 167°                                                                C,63.5 H,5.0 N,9.3                                                            Cl,11.7                                                                            C,63.4 H,4.4                                                                  N,9.0 Cl,12.0       7                                                                                 ##STR7##              A  toluene                                                                             98° C. 1.5 hours COCl.sub.2                                                       72 173- 174°                                                                  C,57.0 H,4.2 N,8.3                                                            Cl,21.0                                                                            C,57.0 H,3.8                                                                  N,8.2 Cl,21.0       8                                                                                 ##STR8##              A  toluene                                                                             95° C. 1.5 hours COCl.sub.2                                                       56 197- 197.5°                                                                 ##STR9##                                                                          C,63.4 H,4.9                                                                  N,9.0 Cl,11.7       9                                                                                 ##STR10##             A  toluene                                                                             92° C. 2 hours COCl.sub.2                                                         14 137- 138°                                                                  C,63.5 H,5.0 N,9.3                                                            Cl,11.7                                                                            C,64.0 H,5.0                                                                  N,8.9 Cl,12.1       10                                                                                ##STR11##             A  benzene                                                                             (CH.sub.3).sub.3 CNH.sub.2                                                               60 142- 144°                                                                  C,59.19 H,4.96                                                                N,7.67 Cl,19.41                                                                    C,58.98 H,5.14                                                                N,6.94 Cl,19.24                                                               5                   11                                                                                ##STR12##             A  benzene                                                                              ##STR13## 66 160.5- 161.5°                                                              C,58.47 H,4.04                                                                N,8.02 Cl,20.30                                                                    C,58.44 H,3.46                                                                N,7.44 Cl,20.19                                                               1                   12                                                                                ##STR14##             A  benzene                                                                              ##STR15## 67 158- 159°                                                                  C,60.48 H,4.80                                                                N,7.42 Cl,18.79                                                                    C,60.79 H,4.84                                                                N,7.46 Cl,18.83                                                               2                   13                                                                                ##STR16##             A  benzene                                                                             (H.sub.5 C.sub.2).sub.2 NH                                                               30 194- 195°                                                                  C,65.33 H,5.86                                                                N,8.47 Cl,10.72                                                                    C,65.81 H,5.83                                                                N,8.27 Cl,10.88                                                               .                   14                                                                                ##STR17##                benzene                                                                              ##STR18## 30 183- 184°                                                                  C,58.80 H,3.50                                                                N,7.89 Cl,20.42                                                                    C,59.13 H,3.41                                                                N,7.81                                                                        Cl,20.41            15                                                                                ##STR19##                benzene                                                                              ##STR20## 43 144.5- 146°                                                                 ##STR21##                                                                         C,56.98 H,4.00                                                                N,7.01 Cl,18.84     16                                                                                ##STR22##                benzene                                                                             H.sub.5 C.sub.2 O(CH.sub.2).sub.2                                             NH.sub.2   60 124.5- 126°                                                                C,56.70 H,4.75                                                                N,7.35 Cl,18.59                                                                    C,56.49 H,4.12                                                                N,6.94 Cl,18.49     17                                                                                ##STR23##                benzene                                                                             CH.sub.3 ONH.sub.2                                                                       23 151.5- 152.5°                                                              C,59.26  H,4.30                                                               N,9.20 Cl,11.63                                                                    C,59.79 H,4.40                                                                N,8.40 Cl, --       18                                                                                ##STR24##                benzene                                                                             (CH.sub.2CCH.sub.2NH).sub.2                                                              -- oil C,61.73 H,4.66                                                                N,7.20 Cl,18.23                                                                    C,61.86 H,4.57                                                                N,6.90 Cl, --       19                                                                                ##STR25##                methanol- water                                                                     (CH.sub.3).sub.2 SO.sub.4                                                                40 84- 86.5°                                                                  C,60.3 H,4.7 N,8.80                                                           Cl,11.13                                                                           C,61.0 H,4.8                                                                  N,9.0 Cl,11.5       20                                                                                ##STR26##                benzene                                                                             (CH.sub.3).sub.2NNH.sub.2                                                                37 152.5- 153°                                                                 C,54.58 H,4.29                                                               N,11.93 Cl,20.14                                                                   C,55.06 H,4.03                                                                N,11.40             __________________________________________________________________________                                                              Cl,20.48             * 19 was obtained by the alkylation of Example 17 using dimethysulfate in     methanolic alkali.                                                       

EXAMPLE 21 Preparation of 2-Chloro-4-nitrobenzophenone Intermediate

Thionyl chloride (35.8 grams, 0.305 mole) was added to a benzenesolution of 2-chloro-4-nitrobenzoic acid (60.3 grams, 0.3 mole) and themixture heated to reflux during 5 hours until the evolution of hydrogenchloride had ceased. Aluminum chloride (100 grams, 0.72 mole) was addedslowly to the stirred solution during a 3.5 hour period and thetemperature rose to 48° C. After the addition, the mixture was warmed to80° C. for 2 hours, cooled, poured onto ice-water (one liter),concentrated hydrochloric acid (90 ml.) added and the mixture warmed at40° C. for 3 hours. Benzene extraction followed by successive treatmentwith 5% aqueous sodium hydroxide, water and calcium chloride yielded,after removal of benzene, a reddish black residue purified byfiltration. The pale yellow solid so obtained was further characterizedas having a melting point equal to 95.5° - 96.5° C. in 44% yields.

EXAMPLE 22

Repeating Example 21 in every detail except that a chlorobenzenesolution of 2-chloro-4-nitrobenzoic acid was employed in lieu of thebenzene solution of the same, there is obtained a 50% yield of2,4'-dichloro-4-nitrobenzophenone in good yield and purity having amelting point of 117° - 117.5° C.

EXAMPLE 23

The procedure of Example 21 is repeated in every detail except that achlorobenzene solution of 4-nitrobenzoic acid is employed in lieu of abenzene solution of 2-chloro-4-nitrobenzoic acid to obtain a 36% yieldof 4'-chloro-4-nitrobenzophenone having a melting point equal to 100° C.to 101° C.

EXAMPLE 24 Preparation of 4-amino-2-chlorobenzophenone

To a solution of 2-chloro-4-nitrobenzophenone (27 grams, 0.103 mole) inhot ethanol (400 ml.) and water (200 ml.) was added iron (30 grams),followed by concentrated hydrochloric acid (25 ml.) dropwise and withstirring. After the addition, the reaction mixture was stirred at refluxduring 1.5 hours, cooled, then made alkaline with ammonium hydroxide andchloroform extracted. After drying the chloroform layer (anhydrousMgSO₄) and filtering, the solution was evaporated to an orange solid,melting point 120° - 130° C. Crystallization from benzene-hexane gavefaint yellow crystals of 4-amino-2-chlorobenzophenone having a meltingpoint of 144° - 145° C., and recovering 16.5 grams which amounts to a69% yield.

On analysis and calculated for C₁₃ H₁₀ NOCl in percent: C, 67.4; H, 4.4;N, 6.1; Cl, 15.3.

Found: C, 67.6; H, 4.2; N, 6.3; Cl, 15.0.

EXAMPLE 25

Employing the procedure of Example 24 and substituting the appropriatenitrobenzophenone for 2-chloro-4-nitrobenzophenone in the reactionyielded the following aminobenzophenones as set forth in the Table IIbelow.

                                      TABLE II                                    __________________________________________________________________________                            Melting                                                                              Analysis (in %)                                                    (%) Point                                                 Aminobenzophenone                                                                              Ex.                                                                              Yield                                                                             (° C.)                                                                        Calcd.                                                                              Found                                    __________________________________________________________________________     ##STR27##       2  96  163-165                                                                              C,58.7 H,3.4 N,5.3 Cl,26.6                                                          C,58.5 H,3.6 N,5.3 Cl,26.6                ##STR28##       3  63  183.5-184                                                                             ##STR29##                                                                          C,67.1 H,4.5 N,6.1 Cl,15.3                ##STR30##       4  45  50-52  N,6.1 N,5.6                                    __________________________________________________________________________

EXAMPLE 26

The postemergence herbicidal activity of the compounds of the presentinvention is demonstrated by the following tests, wherein a variety ofmonocotyledonous and dicotyledonous plants are treated with testcompounds dispersed in aqueous-acetone mixtures. In the tests, seedlingplants are grown in jiffy flats for about two weeks. The test compoundsare dispersed in 50/50 acetone/water mixtures in sufficient quantity toprovide the equivalent of about 0.125 to 4 pounds per acre of activecompound when applied to the plants through a spray nozzle operating at40 psi. for a predetermined time. After spraying, the plants are placedon greenhouse benches and are cared for in the usual manner,commensurate with conventional greenhouse practices. Two weeks aftertreatment, the seedling plants are examined and rated according to therating system provide below. The data obtained are reported in Table IIIbelow.

Plant Species:

MC -- Annual morning-glory

COT -- cotton

SB -- sugar beet

SOY -- soybean

COR -- corn

WO -- wild oats

BA -- barnyard grass

FOX -- green foxtail

MI -- foxtail millet

RAG -- ragweed

MU -- mustard

LA -- lambsquarters

KO -- kochia

    ______________________________________                                                           % Difference in Growth                                     Rating System:     from the Check*                                            ______________________________________                                        0 --  no effect        O                                                      1 --  possible effect   1-10                                                  2 --  slight effect    11-25                                                  3 --  moderate effect  26-40                                                  5 --  definite injury  41-60                                                  6 --  herbicidal effect                                                                              61-75                                                  7 --  good herbicidal effect                                                                         76-90                                                  8 --  approaching complete kill                                                                      91-99                                                  9 --  complete kill    100                                                    4 --  abnormal growth i.e. a definite physiological mal-                            formation but with an over-all effect less than a                             5 on the rating scale.                                                  ______________________________________                                         *based on visual determination of stand, size, vigor chlorosis, growth        malformation and over-all plant appearance.                              

                                      TABLE III                                   __________________________________________________________________________                            ANNUAL WEEDS               CROPS                      STRUCTURE               KO LA MU PI                                                                              Rag                                                                              BA CR GRF                                                                              WO MI                                                                              COR                                                                              COT                                                                              SOY                                                                              SB               __________________________________________________________________________     ##STR31##             .sup.1 2 3                                                                        9 7 9                                                                            9 9 9                                                                            9 7 2                                                                           9 5 5                                                                            7 3 5                                                                            9 2 3                                                                            9 8 8                                                                            8 7 2                                                                              9 3 --                                                                           9 9 8                                                                            9 8 3                                                                            9 8 8             ##STR32##                                                                                            ##STR33##                                                                      9 9 9                                                                           9 9 8 9                                                                          9 9 9 9                                                                          9 9 9 9                                                                         9  1 1 1 1                                                                          2 1 1 1                                                                          1 1 0  0                                                                         1 0 0 0                                                                            0 0 1 0                                                                          0 1 1 0                                                                          2 1 1 9                                                                          9 9 9 9           ##STR34##             .sup.1 2 3                                                                        6 3 1                                                                            9 9 3                                                                            1 1 0                                                                           0 0 0                                                                            2 1 0                                                                            5 3 0                                                                            2 2 1                                                                            1 1 0                                                                              1 1 0                                                                            8 5 8                                                                            3 2 1                                                                            6 8 0             ##STR35##             .sup.2 3 4 5                                                                      9 9 9 9                                                                          9 9 9 9                                                                          9 -- 9 8                                                                        7 7 9 3                                                                          6 7 7 6                                                                          9 9 8 2                                                                          9 8 9 9                                                                          3 3 3 3                                                                            7 7 -- --                                                                        9                                                                                7 3 -- --                                                                        9 9 -- --         ##STR36##                                                                                            ##STR37##                                                                        8 9 7 9                                                                          9 9 9 9                                                                          9 9 8 2                                                                         3 0 0 0                                                                          5 3 3 1                                                                          3 1 2 1                                                                          5 3 2 1                                                                          1 1 0 0                                                                            1 1 0 --                                                                         1 1 0 --                                                                         1 1 1 --                                                                         9 9 9 --          ##STR38##             .sup.2 3 4 5                                                                      8 5 8 8                                                                          9 9 9 9                                                                          9 9 9 8                                                                         9 9 9 9                                                                          6 5 5 2                                                                          8 8 7 2                                                                          8 9  9 8                                                                         3 2 5 1                                                                            9 7 -- --                                                                        9 9 -- --                                                                        8 8 -- --                                                                        9 9 --           __________________________________________________________________________                                                                 --               TREATMENT LB/A                                                                .sup.1 4                                                                      .sup.2 1                                                                      .sup.3 1/2                                                                    .sup.4 1/4                                                                    .sup.5 1/8                                                                

EXAMPLE 27

The selective preemergence herbicidal activity of the compounds of theinvention is exemplified by the following tests in which the seeds of avariety of monocotyledonous and dicotyledonous plants are separatelymixed with potting soil and planted on top of approximately one inch ofpotting soil in separate pint cups. After planting, the cups are sprayedwith the selected aqueous-acetone solution containing test compound insufficient quantity to provide the equivalent of about 1 to 9 pounds peracre of test compound per cup. The treated cups are then placed ongreenhouse benches and cared for in accordance with greenhouseprocedures. Three weeks after treatment, the tests are terminated andeach cup is examined and rated according to the rating system set forthin the previous example. The tabulated results of these tests establishthe herbicidal proficiency of the test compounds and are reported inTable IV below.

                                      TABLE IV                                    __________________________________________________________________________                            ANNUAL WEEDS                CROPS                     STRUCTURE               KO LA MU PI                                                                              Rag                                                                              BA CR GRF                                                                              WO MI                                                                              COR                                                                              COT                                                                              SOY                                                                              SB               __________________________________________________________________________     ##STR39##             .sup.1                                                                            7  9  5 9  3  7  1  0                               ##STR40##             .sup.2 3                                                                       3 0                                                                              2 0                                                                              9 8                                                                              3 0                                                                             3 3                                                                              0 0                                                                              0 0                                                                              0 0                                                                              0 0                             ##STR41##                                                                                            ##STR42##                                                                     9 7 3                                                                            9 9 3                                                                            9 8 6                                                                            9 8 3                                                                              0 0 0                                                                            2 0 0                                                                            8 0 0                                                                            1 0 0                                                                              2 0 0                                                                            0 1 0                                                                            0 0 0                                                                            9 9 0             ##STR43##             .sup.1 4                                                                          6 2                                                                              5 2                                                                              0 0                                                                             7 0                                                                              1 0                                                                              1 0                                                                              0 0                                                                              0 0  1 0                                                                              1 0                                                                              1 0                                                                              0 0               ##STR44##             .sup.1 4 5                                                                        9 6 0                                                                            7 6 1                                                                            9 9 6                                                                           5 0 0                                                                            0 0 0                                                                            0 0 0                                                                            0 0 0                                                                            3 0 0                                                                              1 0 0                                                                            0 0 0                                                                            0 0 0                                                                            8 3 0             ##STR45##                                                                                            ##STR46##                                                                        9 8 2                                                                            9 7 2                                                                            9 5 2                                                                           0 0 0                                                                            1 0 0                                                                            0 0 0                                                                            0 0 0                                                                            0 0 0                                                                              1 0 0                                                                            0 0 0                                                                            0 0 0                                                                            3  7 0            ##STR47##             .sup.1 4 5                                                                        9 9 1                                                                            9 8 0                                                                            9 9 3                                                                           7 2 0                                                                            1 0 0                                                                            6 0 0                                                                            2 0 0                                                                            0 0 0                                                                              0 0 0                                                                            0 0 0                                                                            0 0 0                                                                            9 9 2            __________________________________________________________________________    TREATMENT LB/A                                                                .sup.1 9                                                                      .sup.2 15                                                                     .sup.3 5                                                                      .sup.4 3                                                                      .sup.5 1                                                                  

I claim:
 1. The compound, 3-(p-benzoyl-phenyl)-1,1-dimethyl urea.
 2. Thecompound, 3-(m-benzoylphenyl)-1,1-dimethyl urea.
 3. The compound,3-(4-benzoyl-3-chlorophenyl)-1,1-dimethyl urea.
 4. The compound,3-[3-chloro-4-(p-chlorobenzoyl)phenyl]-1,1-dimethyl urea.
 5. Thecompound, 3-[p-(p-chlorobenzoyl)-phenyl]-1,1-dimethyl urea.